This invention relates to switch assembly structure for dynamoelectric machinery and more particularly to an improved structure for a switch assembly which can be utilized in any one of several forms in conjunction with centrifugal actuators for selectively energizing windings of dynamoelectric machines.
U.S. Pat. No. 4,034,173, issued to William D. Crow on July 5, 1977 discloses and describes a number of dynamoelectric machines, such as split phase induction motors and capacitor start motors, which utilize at least two windings for "start" and "run" operating conditions. These motors include stator and rotor assemblies, the rotor assembly including a shaft and the stator assembly including a plurality of windings. As is known in the art, selective energization of windings is used to generate suitable forces for rotating the rotor assembly in both "start" and "run" conditions. For example, a rotating field may be established in a single-phase motor through an auxiliary or starting winding having current out of phase with the current in the main winding. The starting winding has a higher resistance than the main or running winding and, to eliminate losses due to the extra resistance, the starting winding is disconnected through a centrifugal actuator after the rotor has attained a desired speed, so as to continue operation by single-phase action alone.
It has been recognized as desirable that switch assemblies utilized for such purposes be low in overall construction, assembly and maintenance costs, provide appropriate contact pressure independent of switch arm position, provide for lost motion adjustment, be readily mountable, minimize contact wear and breakage and reduce construction, maintenance, operation and replacement costs. The modified switch assembly of the present invention recognizes and accomplishes these desired features, providing a switch assembly structure which requires a minimum of contact pressure, avoids undesirable variations in contact force by utilization of flat, flexible conductive members and provides a maximum of rolling wipe-action contact to reduce contact wear and breakage. In addition, the switch assembly of the present invention effectively utilizes switch arm action to ensure positive and continued electrical contact maintenance, readily accommodating for conventional machinery impact and vibration.
Various other features of the present invention will become obvious to one skilled in the art upon reading the disclosure set forth herein.